Question

which angles are vertical angles?

Explanation:

Step1: Recall vertical - angle definition

Vertical angles are formed when two lines intersect. They are non - adjacent angles opposite each other.

Step2: Analyze each option

For two lines to form vertical angles, they must intersect at a point. In the given figure, when two lines intersect at a point, the non - adjacent opposite angles are vertical angles. $\angle GHE$ and $\angle IHJ$ are formed by the intersection of two lines at point $H$, and they are non - adjacent and opposite to each other.

Answer:

$\angle GHE$ and $\angle IHJ$